Patrick, You make a number of valid points. They are, however, mute. A1:2000 to CISPR 22:1997 was published in 2000 and is being adopted around the world. As a result, if regulatory bodies do not adopt it, we get to perform radiated emissions tests twice on products, which will have a substantial cost impact on the ITE industry.
The whole purpose of the clamps is to improve repeatability between labs. The impact on the measured emissions levels was pointed out during the discussions within CISPR SC G with no effect. We're stuck with them, for better or worse. We need the FCC to allow them to reduce duplicate testing. The FCC is well aware of the dual testing that their not approving the clamps will cause. I have personally pointed that out to them in meetings. We'll see what happens. Ghery -----Original Message----- From: Conway, Patrick R [mailto:conw...@louisville.stortek.com] Sent: Thursday, November 21, 2002 1:12 PM To: 'Pettit, Ghery'; 'emc-p...@majordomo.ieee.org' Subject: RE: Ferrite clamps Gherry- It will be interesting to see if ITI are successful with the FCC on this topic. The ferrite clamp devices seem to be counter productive to the original intent of the laws. I may be *way* off base here but I'll explain: Point #1- It seems to me that the original intent behind the Part 15 Unintentional Radiator requirements was to protect licensed operators from the "noise" generated by digital devices. The original limits and test methods were widely scrutinized over the years. They have also been updated and adjusted as necessary. As Jim Bacher pointed out in an earlier email on this thread, the limits and methods have been shown to protect those licensed services from interference. So- I'm sure the FCC will be asking: "if it isn't broke, why fix it" (my words, not theirs!!). Point #2- Since data exists showing that the clamps *decrease* emissions during a test, couldn't the use of a clamp let a product into the market that could potential *cause* interference? (it isn't broke- but this change may break it) Point #3- For as long as I can remember, if a ferrite bead is put on a cable during testing then that *exact* cable with that *exact* ferrite bead has to be delivered to the customer along with the product. How does the floor mounted ferrite get an exception to this? I can understand the motivation of a lab owner wanting to have agreeable measurements with another lab. It's good business for him to say he can agree with any one else. However- if the foundation for the rules is to decrease interference problems then aren't we (the compliance community) a little off-base on this one ? Maybe I'm missing some important details here. Someone correct me if I'm wrong... Best Regards, Patrick Conway NCE EMC Advisory Engineer 303.661.6391 303.661.6717 (FAX) -----Original Message----- From: Pettit, Ghery [mailto:ghery.pet...@intel.com] Sent: Wednesday, November 20, 2002 5:30 PM To: Conway, Patrick R; Pettit, Ghery; 'emc-p...@majordomo.ieee.org' Subject: RE: Ferrite clamps Patrick, The whole reason for A1:2000 to CISPR 22:1997 was to improve repeatability between labs. I agree with your concern about it causing double testing for radiated emissions from 30 MHz to 1000 MHz until all regulatory bodies accept the ferrite clamps. Not a good thing. I am working through an industry association (ITI) to get the FCC to accept them. I've been working on this for 2 years. Nothing so far, other than some work in ANSI C63 that might result in the clamps being added to C63.4, maybe in 2004. Ghery Pettit Intel -----Original Message----- From: Conway, Patrick R [mailto:conw...@louisville.stortek.com] Sent: Tuesday, November 19, 2002 11:42 AM To: 'Pettit, Ghery'; 'emc-p...@majordomo.ieee.org' Subject: RE: Hello Ghery- Thank you for the information. To be honest, I'm not all that familiar with the CISPR voting process but I do recognize that any election with a 1 vote margin must be a bit contentious. Unless of course you live in Florida where every vote counts AT LEAST once. There wasn't any "hanging chad" during that CISPR vote, was there? But- back to A1:2000: The data you report indicates that the emission profile will change with the addition of the ferrite clamps. This is bothersome for (at least) three reasons- 1st: if the ferrite clamp reduces the emissions from a frequency or two then I can achieve compliance but a customer may experience an interference problem due to the fact that they do not install the ferrite clamp at their facility. 2nd: if the ferrite clamp increases emissions from a frequency then a product that now achieves compliance may have to be redesigned in order to pass after the DOW. 3rd: since the FCC doesn't presently allow the use of the ferrite clamps then I have to test each product one more time- this adds cost and time delay- especially if a failure arises due to this test. This could be a major headache for people who deliver product to market in Europe. Can anyone tell us the driving reason behind this regulation? Was it to increase repeatability at test sites? Was it to reduce the number of interference complaints from ITE installations? Best Regards, Patrick Conway NCE StorageTek EMC Advisory Engineer 303.661.6391 303.661.6717 (FAX) -----Original Message----- From: Pettit, Ghery [mailto:ghery.pet...@intel.com] Sent: Monday, November 18, 2002 10:09 PM To: Conway, Patrick R; 'emc-p...@majordomo.ieee.org' Subject: RE: Patrick, I performed some A/B comparison measurements several years ago when this was still working its way through CISPR to aid in the determination of the US vote. I found that some emissions go down (some by a bunch) and others may go up when you add the clamps. You will need to re-test products for Europe as you can't predict what the change will by just by inspection. BTW, this amendment to CISPR 22 passed by 1 vote. The US voted no as the clamps were not adequately defined in the proposal. Ghery Pettit Intel -----Original Message----- From: Conway, Patrick R [mailto:conw...@louisville.stortek.com] Sent: Monday, November 18, 2002 2:53 PM To: 'emc-p...@majordomo.ieee.org' Subject: All- I'd like to know if there are any opinions about... It is my understanding the CISPR 22 A1:2000 will require the use of "ferrite clamps" during RE tests of table-top equipment. Has anyone started using these devices during their testing? Has anyone seen a difference in their test results with the use of these devices? Best Regards, Patrick Conway NCE StorageTek EMC Advisory Engineer 303.661.6391 303.661.6717 (FAX) ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on "browse" and then "emc-pstc mailing list" ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on "browse" and then "emc-pstc mailing list" ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on "browse" and then "emc-pstc mailing list"
